Disazo dyes



United StateslPatcnt O 3,100,769 DISAZG DYES Ermanno Gaetani, Milan,Italy, assignor to Aziende Colori Nazionali Atfini ACNA S.p.A-, Milan,Italy, a

corporation of Italy No Drawing. Filed Apr. 14, 1960, Ser. No. 22,125

Claims priority, application Italy Dec. 15, 1959 5 Claims. (Cl. 260-186)An object of the present invention is to provide certain new waterinsoluble disazo dyes having in the general Formula A:

R (IDCHa The compounds of general Formula A, are obtained by coupling inthe presence of a strong base, one mol of an amino azo compound of thetype:

III OCH:

2 wherein R and R have the above mentioned meaning and R is hydrogen,with one mol of a compound of the type:

Example 1 12.3 g. 1-amino-2-methoxy-benzene are diazotised and coupledwith a l-amino-Z,S-dimethoxy-azobenzene solution (15.5 g.) in aconventional manner. The aminoazo dye obtained is filtered, washed anddispersed in 300 g. water and 30 g. hydrochloric acid solution, and isthen diazotised with a solution of 7 g. sodium nitrite in 30 g. water(at about 10 C.). The diazo-azo compound solution is filtered andcoupled with a solution of 12 g. para-methylphenol in 200 g. water and14 g. of a sodium hydroxide solution (36 B), while dropping in at thesame time 30 g. of a 30% ammonia solution.

The disazo dye obtained is filtered, washed until it is neutral anddried. This dye consists of a very dark powder (melting point: 164 C.)having the formula:

cons ?C 3 om (B 0 H3 (5 H Upon chromatographic examination, a uniformred spot is observed which turns to a bluish shade upon treatment withalkalies and with acids, but this change occurs more slowly with theacids.

Example 2 This dye is obtained by operating as described in Example 1but using 15.5 g. fi-naphthol instead of p-methylphenol. The dyeobtained, having the formula is a bluish powder (melting point 250 C.with decomposition). Upon chromatography a uniform violet spot whichremains unaltered with alkalies (the spot is slightly modified to acids)is observed.

Example 3 12.3 g. l-amino-Z-methoxy-benzene are diazotised and coupledwith a 1-amino-Z-methoxy-S-methyl-benzene solution (13.5 g.). Theamino-azo dye thus obtained is diazotised and coupled with fl-naphtholas described in the preceding examples.

A dye consisting of a bluish powder (melting point 254 C.) and havingthe following formula is obtained:

CIJCH: OOHz OH Uponjchfomatographic examination, -a uniform violet spotwhich does not turn upon contact with acids and alkalies 's; obtained.

Example 4 29. 6 g; 4-amino-2,5-dimethoxy-azobenzene are diazog! inconventional manner and the solutionof the diazozodye is added (at atemperature below 5 C.) to a ution of 17.5 g. 1-methy1-4-naphthol, whileoperating 'in'the preceding examples. The disazo dye obtained,

havi ng the formula:

is abronzy dark powder (melting point 213.? 0.), p j I Uponchromatographic examination a-uniforrn violet h '7 spot which turnsslightly to blue with alkalis and acids is observed. I Y

Having thus described the invention, what I desire to secure and claimbyLetters Patent is: 4' t a V p 1 1-1, A disazoydye, insoluble inrwater,se'lectedgfromthe groupconsisting of dyes of theform'ulaez" I 2. Adisazo dye, insoluble in water havingthe following formulaz. 4 o

om OH ,4. A disazo dye, insoluble innwateghaving the fol1ow- UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 100,769August 13 1963 Ermanno Gaetani It is hereby certified that error appearsin the above numbered patent requiring correction and that the saidLetters Patent should read as corrected below.

Column 4,, lines 3 to 9, strike out the following formula:

OCH OH ON N N=N Signed and sealed this 7th day of April 1964.

(SEAL) EDWARD J BRENNER Attest:

ERNEST Wo SWIDER Attesting Officer Commissioner of Patents

1. A DISAZO DYE, INSOLUBE IN WATER SELECTED FROM THE GROUP CONSISTING OFDYES OF THE FORMULAE: